Network Analysis Reveals the Combination of Controlled-Release and Regular Urea Enhances Microbial Interactions and Improves Maize Yields.

Increased complexity of microbial networks can contribute to increased biodiversity and multifunctionality and thus crop productivity. However, it is not clear which combination ratio of regular and controlled-release urea will increase the soil microbial community complexity and improve maize yield in the North China Plain. To address this knowledge gap, a 2-year field experiment was conducted to explore the effects of the combination of regular (U) and controlled release (S) urea ratios [no fertilizer control (CT), regular urea alone (U), controlled-release urea alone (S), controlled-release urea mixed with regular urea 3:7 (SU3), controlled-release urea mixed with regular urea 5:5 (SU5), and controlled-release urea mixed with regular urea 7:3 (SU7)] on XianYu 688 yield and its rhizosphere and bulk soil microbial community composition and network complexity at different fertility stages. The combination of controlled-release and regular urea increased the N agronomic efficiency, N partial factors productivity, maize yield, and grain number per spike, with the maximum maize yield (9,186 kg ha-1) being achieved when the ratio of controlled-release urea to regular urea was 3:7 (SU3, p < 0.05). Maize yield increased by 13% in the SU3 treatment compared to the CT treatment. Rhizosphere soil microbial diversity remained stable at the silking stage of maize while increased at the physiological maturity stage of maize, with the increasing controlled-release to regular N fertilizer ratios (from 3:7 to 7:3, p < 0.05). This result suggests that a combination of regular and controlled-release N fertilizer can still substantially increase soil microbial diversity in the later stages of maize growth. The combination of controlled-release and regular urea is more effective in improving microbial network total links and average degree, and N agronomic efficiency (R 2 = 0.79, p < 0.01), N partial factor productivity (R 2 = 0.79, p < 0.01), spikes per unit area (R 2 = 0.54, p < 0.05), and maize yield (R 2 = 0.42, p < 0.05) increased with the microbial network complexity. This result indicates that the higher microbial network complexity is strongly associated with the higher N agronomic efficiency and N partial factors productivity and maize yield. In conclusion, the ratio of controlled-release to regular urea at SU3 not only increases the yield of maize and N agronomic efficiency but also enhances microbial diversity and network complexity in the North China Plain.

Effect of polyaspartic acid and different dosages of controlled-release fertilizers on nitrogen uptake, utilization, and yield of maize cultivars.

The effects of polyaspartic acid and different controlled-release fertilizers with urea on dry matter accumulation and distribution, nitrogen absorption and accumulation, and the activities of enzymes involved nitrogen metabolism and yield of corn were studied by using xianyu (XY688), a maize nitrogen efficient cultivar, and Jifeng NO.2 (JF2), a maize nitrogen-inefficient cultivar, as experimental materials and through random blocks experimental design in 2019. For XY688, polyaspartic acid chelated nitrogen fertilizer (PASPN) had the highest yield, which was 21.34% higher than N0 treatment. For JF2, it also had the highest yield under PASPN combined urea treatment, which was 23.44% higher than N0 (no nitrogen fertilizer), and JF2 had a 9.7% lower yield under XY688 treatment. For XY688, PASPN treatment had the largest nitrogen uptake in grain, up to 3.14 kg/hm2, and PASPN treatment increased 17.4% compared with N0. For JF2, grain nitrogen uptake was also the highest under PASPN treatment, which was significantly different from other treatments. Nitrogen uptake was 3.16 kg/hm2, which increased 37.4% compared with N0. Compared with JF2, XY688 showed higher nitrogen uptake efficiency, nitrogen utilization efficiency, and partial nitrogen productivity. For XY688, the highest nitrogen absorption efficiency was SU3 (slow-release urea and ordinary urea) treatment (0.36 kg/kg). The partial nitrogen productivity and harvest index of PASPN treatment were the highest and significantly different from other treatments. The partial nitrogen productivity of PASPN treatment was 57.02 kg/kg. These results can provide help for the further researches of the rational utilization and absorption of nitrogen fertilizer.

Evaluating the effectiveness of university agricultural extension test stations using Wuli-Shili-Renli methodology / Avaliação da eficácia de estações de teste de extensão agrícola universitária usando a metodologia Wuli-Shili-Renli

ABSTRACT: Wuli-Shili-Renli (WSR) methodology was used to assess the effects of systematic management on university agricultural extension test stations, in order to understand areas for further optimization. We developed a framework model and evaluation index system, of which, the weights of the evaluation index system were determined using AHP. Using an agricultural extension test station of Hebei Agricultural University as an example, we interviewed and surveyed in total of 225 university extension experts from nine test stations. Assessment showed that the test station system organization produces desirable societal benefits and improvements. In addition, the organizational structure and job allocation were found to act as high-impact factors in improving the optimal system function, with the university extension experts functional better in the incentive and guarantee mechanism than other factors. Our investigation validated that the university extension experts were critical in designing the incentives and evaluation programs.

RESUMO: A metodologia Wuli-Shili-Renli (WSR) foi usada para avaliar os efeitos do manejo sistemático nas estações de teste de extensão agrícola da universidade, a fim de entender as áreas para maior otimização. Desenvolvemos um modelo de estrutura e um sistema de índices de avaliação, dos quais os pesos do sistema de índices de avaliação foram determinados com o AHP. Usando uma estação de teste de extensão agrícola da Universidade Agrícola de Hebei como exemplo, entrevistamos um total de 225 especialistas em extensão universitária de nove estações de teste. A avaliação mostrou que a organização do sistema da estação de teste produz benefícios e melhorias sociais desejáveis. Além disso, verificou-se que a estrutura organizacional e a alocação de cargos atuam como fatores de alto impacto na melhoria da função ótima do sistema, com os especialistas em extensão universitária funcionando melhor no mecanismo de incentivo e garantia do que outros fatores. Nossa investigação validou que os especialistas em extensão universitária eram críticos no desenho dos incentivos e programas de avaliação.